Try to detect single-valued returns in AWS

Lambdas generally only deal with single values anyway, but for
consistency we should return similar results from a Lambda handler
as from an MVC handler in s-c-f-web.

spring-cloud-function-adapters/spring-cloud-function-adapter-aws/src/test/java/org/springframework/cloud/function/adapter/aws/SpringBootRequestHandlerTests.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright 2016-2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.function.adapter.aws;
+
+import java.util.function.Function;
+
+import org.junit.Test;
+
+import org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration;
+import org.springframework.cloud.function.context.ContextFunctionCatalogAutoConfiguration;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Dave Syer
+ *
+ */
+public class SpringBootRequestHandlerTests {
+
+	private SpringBootRequestHandler<Foo, Bar> handler;
+
+	@Test
+	public void functionBean() throws Exception {
+		handler = new SpringBootRequestHandler<Foo, Bar>(FunctionConfig.class);
+		handler.initialize();
+		Object output = handler.handleRequest(new Foo("foo"), null);
+		assertThat(output).isInstanceOf(Bar.class);
+	}
+
+	@Configuration
+	@Import({ ContextFunctionCatalogAutoConfiguration.class,
+			JacksonAutoConfiguration.class })
+	protected static class FunctionConfig {
+		@Bean
+		public Function<Foo, Bar> function() {
+			return foo -> new Bar(foo.getValue().toUpperCase());
+		}
+	}
+
+	protected static class Foo {
+		private String value;
+
+		public Foo(String value) {
+			this.value = value;
+		}
+
+		public String getValue() {
+			return value;
+		}
+
+		public void setValue(String value) {
+			this.value = value;
+		}
+	}
+
+	protected static class Bar {
+		private String value;
+
+		public Bar() {
+		}
+
+		public Bar(String value) {
+			this.value = value;
+		}
+
+		public String getValue() {
+			return value;
+		}
+
+		public void setValue(String value) {
+			this.value = value;
+		}
+	}
+}

spring-cloud-function-adapters/spring-cloud-function-adapter-aws/src/test/java/org/springframework/cloud/function/adapter/aws/SpringBootStreamHandlerTests.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright 2016-2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.function.adapter.aws;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.util.function.Function;
+
+import org.junit.Test;
+
+import org.springframework.boot.autoconfigure.jackson.JacksonAutoConfiguration;
+import org.springframework.cloud.function.context.ContextFunctionCatalogAutoConfiguration;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Dave Syer
+ *
+ */
+public class SpringBootStreamHandlerTests {
+
+	private SpringBootStreamHandler handler;
+
+	@Test
+	public void functionBean() throws Exception {
+		handler = new SpringBootStreamHandler(FunctionConfig.class);
+		handler.initialize();
+		ByteArrayOutputStream output = new ByteArrayOutputStream();
+		handler.handleRequest(new ByteArrayInputStream("{\"value\":\"foo\"}".getBytes()),
+				output, null);
+		assertThat(output.toString()).isEqualTo("{\"value\":\"FOO\"}");
+	}
+
+	@Configuration
+	@Import({ ContextFunctionCatalogAutoConfiguration.class,
+			JacksonAutoConfiguration.class })
+	protected static class FunctionConfig {
+		@Bean
+		public Function<Foo, Bar> function() {
+			return foo -> new Bar(foo.getValue().toUpperCase());
+		}
+	}
+
+	protected static class Foo {
+		private String value;
+
+		public String getValue() {
+			return value;
+		}
+
+		public void setValue(String value) {
+			this.value = value;
+		}
+	}
+
+	protected static class Bar {
+		private String value;
+
+		public Bar() {
+		}
+
+		public Bar(String value) {
+			this.value = value;
+		}
+
+		public String getValue() {
+			return value;
+		}
+
+		public void setValue(String value) {
+			this.value = value;
+		}
+	}
+}